Aggregate Particles in the Plumes of Enceladus

Estimates of the total particulate mass of the plumes of Enceladus are important to constrain theories of particle formation and transport at the surface and interior of the satellite. We revisit the calculations of Ingersoll & Ewald (2011), who estimated the particulate mass of the Enceladus plumes from strongly forward scattered light in Cassini ISS images. We model the plume as a combination of spherical particles and irregular aggregates resulting from the coagulation of spherical monomers, the latter of which allows for plumes of lower particulate mass. Though a continuum of solutions are permitted by the model, the best fits to the ISS data consist either of low mass plumes composed entirely of small aggregates or high mass plumes composed of mostly spheres. The high particulate mass plumes have total particulate masses of (166 $\pm$ 42) $\times$ 10$^3$ kg, consistent with the results of Ingersoll & Ewald (2011). The low particulate mass plumes have masses of (25 $\pm$ 4) $\times$ 10$^3$ kg, leading to a solid to vapor mass ratio of 0.07 $\pm$ 0.01 for the plume. If indeed the plumes are made of such aggregates, then a vapor-based origin for the plume particles cannot be ruled out. Finally, we show that the residence time of the monomers inside the plume vents is sufficiently long for Brownian coagulation to form the aggregates before they are ejected to space.Comment: 44 pages, 8 figures, 2 tables, Published in Icaru

On the minimal number of critical points of functions on h-cobordisms

Let (W,M,M'), dim W > 5, be a non-trivial h-cobordism (i.e., the Whitehead torsion of (W,V) is non-zero). We prove that every smooth function f: W --> [0,1], f(M)=0, f(M')=1 has at least 2 critical points. This estimate is sharp: W possesses a function as above with precisely two critical points.Comment: 7 pages, Late

A Tale of Two Imperial Residences: Aurangzeb's Architectural Patronage

While the Mughal Emperor Aurangzeb Alamgir is not well-known for his architectural commissions as his predecessors, there are still a few extant buildings associated with him. Two of these are residential sites, built almost fifty years apart, at the beginning and end of his career as an emperor. This essay examines these hitherto unpublished sites, and documents them as part of a Mughal legacy in the Deccan that has remained uncelebrated. The palace at Aurangabad and a royal residential compound just outside of Ahmadnagar are the two sites which bracket the emperor's career and offer an insight into his political fortunes and religious life as it changed

Quantum K-theory of Quiver Varieties and Many-Body Systems

We define quantum equivariant K-theory of Nakajima quiver varieties. We discuss type A in detail as well as its connections with quantum XXZ spin chains and trigonometric Ruijsenaars-Schneider models. Finally we study a limit which produces a K-theoretic version of results of Givental and Kim, connecting quantum geometry of flag varieties and Toda lattice.Comment: v3: 33 pages, some clarifications and correction

Colloidal diffusion and hydrodynamic screening near boundaries

The hydrodynamic interactions between colloidal particles in small ensembles are measured at varying distances from a no-slip surface over a range of inter-particle separations. The diffusion tensor for motion parallel to the wall of each ensemble is calculated by analyzing thousands of particle trajectories generated by blinking holographic optical tweezers and by dynamic simulation. The Stokesian Dynamics simulations predict similar particle dynamics. By separating the dynamics into three classes of modes: self, relative and collective diffusion, we observe qualitatively different behavior depending on the relative magnitudes of the distance of the ensemble from the wall and the inter-particle separation. A simple picture of the pair-hydrodynamic interactions is developed, while many-body-hydrodynamic interactions give rise to more complicated behavior. The results demonstrate that the effect of many-body hydrodynamic interactions in the presence of a wall is much richer than the single particle behavior and that the multiple-particle behavior cannot be simply predicted by a superposition of pair interactions

FRAP Analysis: Accounting for Bleaching during Image Capture

The analysis of Fluorescence Recovery After Photobleaching (FRAP) experiments involves mathematical modeling of the fluorescence recovery process. An important feature of FRAP experiments that tends to be ignored in the modeling is that there can be a significant loss of fluorescence due to bleaching during image capture. In this paper, we explicitly include the effects of bleaching during image capture in the model for the recovery process, instead of correcting for the effects of bleaching using reference measurements. Using experimental examples, we demonstrate the usefulness of such an approach in FRAP analysis.Molecular and Cellular Biolog

A Ground-Based Albedo Upper Limit for HD 189733b from Polarimetry

We present 50 nights of polarimetric observations of HD 189733 in $B$ band using the POLISH2 aperture-integrated polarimeter at the Lick Observatory Shane 3-m telescope. This instrument, commissioned in 2011, is designed to search for Rayleigh scattering from short-period exoplanets due to the polarized nature of scattered light. Since these planets are spatially unresolvable from their host stars, the relative contribution of the planet-to-total system polarization is expected to vary with an amplitude of order 10 parts per million (ppm) over the course of the orbit. Non-zero and also variable at the 10 ppm level, the inherent polarization of the Lick 3-m telescope limits the accuracy of our measurements and currently inhibits conclusive detection of scattered light from this exoplanet. However, the amplitude of observed variability conservatively sets a $3 \sigma$ upper limit to the planet-induced polarization of the system of 58 ppm in $B$ band, which is consistent with a previous upper limit from the POLISH instrument at the Palomar Observatory 5-m telescope (Wiktorowicz 2009). A physically-motivated Rayleigh scattering model, which includes the depolarizing effects of multiple scattering, is used to conservatively set a $3 \sigma$ upper limit to the geometric albedo of HD 189733b of $A_g < 0.37$. This value is consistent with the value $A_g = 0.226 \pm 0.091$ derived from occultation observations with HST STIS (Evans et al. 2013), but it is inconsistent with the large $A_g = 0.61 \pm 0.12$ albedo reported by (Berdyugina et al. 2011).Comment: 10 pages, 9 figures, submitted to Ap

Reflected Light Curves, Spherical and Bond Albedos of Jupiter- and Saturn-like Exoplanets

Reflected light curves observed for exoplanets indicate that a few of them host bright clouds. We estimate how the light curve and total stellar heating of a planet depends on forward and backward scattering in the clouds based on Pioneer and Cassini spacecraft images of Jupiter and Saturn. We fit analytical functions to the local reflected brightnesses of Jupiter and Saturn depending on the planet's phase. These observations cover broadbands at 0.59–0.72 and 0.39–0.5 μm, and narrowbands at 0.938 (atmospheric window), 0.889 (CH4 absorption band), and 0.24–0.28 μm. We simulate the images of the planets with a ray-tracing model, and disk-integrate them to produce the full-orbit light curves. For Jupiter, we also fit the modeled light curves to the observed full-disk brightness. We derive spherical albedos for Jupiter and Saturn, and for planets with Lambertian and Rayleigh-scattering atmospheres. Jupiter-like atmospheres can produce light curves that are a factor of two fainter at half-phase than the Lambertian planet, given the same geometric albedo at transit. The spherical albedo is typically lower than for a Lambertian planet by up to a factor of ~1.5. The Lambertian assumption will underestimate the absorption of the stellar light and the equilibrium temperature of the planetary atmosphere. We also compare our light curves with the light curves of solid bodies: the moons Enceladus and Callisto. Their strong backscattering peak within a few degrees of opposition (secondary eclipse) can lead to an even stronger underestimate of the stellar heating

Pathology of heart, coronaries and aorta in autopsy cases with history of sudden death: an original article

Background: Natural deaths represent a large proportion of sudden (unexpected and unattended) deaths. The term “sudden cardiac death” (SCD) refers to death from the abrupt cessation of cardiac function due to cardiac arrest. The objective of this study was to identify various causes, risk factors, age and sex distribution associated with sudden cardiac death in an Indian setting.Methods: Detail review of medical records and an autopsy study of all cases of sudden cardiac death that occurred instantaneously or within 24 hours of onset of symptoms in a tertiary care institution, between December 2010 and December 2015 was carried out.Results: In total, 124 cases of sudden death were studied during this period. Out of 124 cases, 109 cases (87.90%) showed pathology in heart and aorta. Atherosclerotic coronary heart disease was the most common cause of death (72.58%) followed by Hypertensive heart disease (4.83%), Hypertrophic cardiomyopathy (3.22%), Myocarditis (3.22%), Infective endocarditis (1.61%), Rheumatic heart disease (0.8%), Aortic dissection (0.8%), and syphilitic aortitis (0.8%).Conclusions: Sudden death is a source of concern and a detailed postmortem examination is mandatory to ascertain its cause. Presence of co-existing conditions like diabetes and hypertension contribute immensely to the risk of sudden death. Occurrence of sudden death at a younger age presents a formidable challenge. Prevention of development of risk factors of atherosclerosis at an early age can be an effective strategy to counter this ailment at all levels

Late pleistocene sedimentation history of the Shirshov Ridge, Bering Sea

The analysis of the lithology, grain-size distribution, clay minerals, and geochemistry of Upper Pleistocene sediments from the submarine Shirshov Ridge (Bering Sea) showed that the main source area was the Yukon–Tanana terrane of Central Alaska. The sedimentary materials were transported by the Yukon River through Beringia up to the shelf break, where they were entrained by a strong northwestward-flowing sea current. The lithological data revealed several pulses of ice-rafted debris deposition, roughly synchronous with Heinrich events, and periods of weaker bottom-current intensity. Based on the geochemical results, we distinguished intervals of an increase in paleoproductivity and extension of the oxygen minimum zone. The results suggest that there were three stages of deposition driven by glacioeustatic sea-level fluctuations and glacial cycles in Alaska